This invention relates to a method to purify Yttrium-90 from its parent, Strontium-90. More specifically, the invention relates to the use of a non-hazardous, commercially available material, to achieve this separation.
Yttrium-90 is a nuclide having important uses in radioactive assays as well as in medicine for a biological tracer. Strontium-90 and Yttrium-90 can be found in many environmental samples such as water, vegetation, and soil.
Separation of Yttrium-90 from its parent Strontium-90 is done with various materials. Most Strontium-90 procedures are precipitation procedures. The classic technique is the use of fuming nitric acid. HDEHP, as well as the use of crown ethers, are other materials that can be used. However, all of the materials used for this separation are listed as hazardous material. In addition, these techniques are relatively expensive as well as time consuming.
Chelex-100.RTM. is a well-known chelating ion-exchange resin trademarked by Bio-Rad Laboratories of Richmond, Calif. It is a bidente ligand having the chemical name iminodiacetic acid mounted on a divinyl benzene substrate. Chelex-100.RTM. has many applications, and is generally used to preconcentrate metals out of brine solutions. This resin has the advantages over the other materials currently in use for separating yttrium-90 from its parent strontium-90. These advantages include high loading capacity, increased flow rate, as well as its comparative inexpense. Table 1 shows a variety of metals that can be preconcentrated on Chelex-100.RTM. resin from various samples. It is noted that there is no listing for the radionuclides Sr-90 or Y-90.
TABLE 1 ______________________________________ Preconcentration of Metals on Chelex-100 .RTM. Resin METAL SAMPLE REFERENCE ______________________________________ Cd, Co, Cr, Cu, Fe, Mn, Natural Kingston et al. Anal. Mo, Ni, Sc, Sn, Th, U, waters Chem, 55, 1160 (1983) V, Zn Cd, Zn, Pb, Fe, Mn, Cu, Seawater Sturgeon, et al., Anal. Ni, Co, Cr Chem., 52, 1585 (1980) Cd, Ce, Co, Cu, Fe, Mn, Seawater Kingston et al., Mo, Ni, Pb, Sc, Sn, Th, Environ. Inter., 10, U, Zn 153 (1984) Fe, Mn, Cu, Ni, Cd, Pb, Seawater Paulson, Anal. Chem., Zn 58, 183 (1986) Fe, Zn, Mn Biological Pella et al., Anal. Materials Chem., 55, 1193 (1983) V Biological Fassett et al., Anal. Materials Chem., 57, 2474 (1985) Cd, Co, Cu, Fe, Mn, Ni, Natural Kingston, Quantitative Pb, Zn waters Ultratrace Transition Metal Analysis of High Salinity Waters Utilizing Chelating Resin Separation, National Technical Information Service, Springfield, VA (1979) Th, Pa, U, Te, Zr, Nb Waste El-Sweify et al., waters Radiochem. Acta, 38, 211 (1985) Fe, Au, Ga, Th, Sb Hydrochloric Koshima, Anal. Sci., 2, acid solution 255 (1986) Cd, Ce, Co, Cr, Cu, Fe, Natural Kingston, et al., The Mn, Mo, Ni, Pb, Sc, Sn, waters Characterization of the Th, U, Zn Chesapeake Bay: A Systematic Analysis of Toxic Trace Elements, NBSIR 83-2698 (1983) As (V), As (III) Industrial Chandra, et al, solutions Reactive Polymers, 8, 85 (1988) Cu, Cd, Mn, Zn, Pb River water Liu et al., Anal. Chem., 61, 525 (1989) Arsenate, Arsenite Industrial Chanda et al., Reactive effluents Polymers, 8, 85 (1988) Cu, Cd, Zn Natural Liu et al., Anal. waters Chem., 61, 520 (1989) ______________________________________
Accordingly, it is an object of the present invention to separate Yttrium-90 from Strontium-90 quickly and efficiently, and without the use of hazardous materials.
It is another object of the present invention to provide a fast and economical chromatographic method for the analysis of Strontium-90/Yttrium-90 in environmental waste streams.